Known in the prior art is a device for administration of medicinal preparations (cf. U.S. Pat. No. 4,055,177, Nov. 25, 1977), comprising a tube, or capsule, confined, on the bottom, by a membrane and separated by a partition and a needle holder into two chambers A and B, a needle unit, and a piston onto which a rod is screwed.
As the rod is pressed upon, the partition moves under the action of the liquid pressure in the chamber A, the partition is punctured against the needle point and broken. The liquid passes through a hollow needle into the chamber B containing the liquid or solid component. As soon as the whole amount of the liquid is passed into the chamber B the cap is removed to release the injection needle the inner end of which breaks the membrane under the action of a spring.
The known injector for administration of medicinal preparations is inconvenient for auto-injection. The sterility of the injection needle cannot be guaranteed. Moreover, the procedure by which the injector is prepared for use is complicated since it is necessary to mix the components by hand, and residual quantities of the liquid can remain in the chamber A. An additional operation dealing with removal of the cap from the needle is also required before the injection. Furthermore, the capsule of the device contains a certain amount of air between the chambers A and B, which is undesirable and should not be injected with the medicinal preparation.
An object of the invention is to provide a device for administration of medicinal preparations, in which the medicinal ingredients can be mixed semiautomatically before injection.
Another object of the invention is to provide a device for administration of medicinal preparations, which will allow convenient auto-injection with the needle remaining sterile.
The invention resides in a device for administration of medicinal preparations, comprising an isolated capsule, inside which, coaxially arranged therewith and with each other are: a main piston limiting a chamber for the first medicinal preparation, and having a channel to pass the second medicinal preparation. The channel is closed by a partition on the side facing the chamber for the first medicinal preparation. An additional piston, and an injection needle, and a drive of the piston made in the form of a spring-loaded pusher are located inside a housing upon which is installed the changeable isolated capsule and inside which there is a stopping member to arrest the spring-loaded pusher. In accordance with the invention, the partition is installed movably, the injection needle is located inside the isolated capsule, and is fixed to the additional piston, passes through the partition and has an aperture in the zone of the partition on the side of the chamber for the first medicinal preparation. The additional piston is located in the channel of the main piston and confines the chamber for the second medicinal preparation, the drive of the pistons has an additional pusher interacting with the additional piston and located coaxially with the spring-loaded pusher, and the pistons drive housing has an additional stopping member to check the movement of the additional spring-loaded pusher.
The design of the device for administration of medicinal preparation ensures separate storage in sterile conditions of medicinal preparations before mixing them, mixing the medicinal preparations semiautomatically by releasing the stopping member of the spring-loaded pusher before the injection, and also provides semiautomatic conditions for auto-injection by releasing the additional stopping member of the additional spring-loaded pusher.
Moreover, the needle remains sterile during all manipulations.